Lord and Lady Greystoke are passengers on a ship bound for Africa. When the ship is taken over by mutineers, the two are left on a tropical coast. They die. Their infant son is adopted by Kala, an ape. She raises him as her own.

The young Tarzan (Gordon Griffith) grows up among the apes. He becomes their king. A sailor discovers Tarzan. He reports to Tarzan's relatives in England. An expedition led by Professor Porter sets off to find Tarzan.